Shelving system

ABSTRACT

A shelving system including a plurality of movable shelves ( 1 ) installed for back-and-forth movement on a travel path through a travel support device, thereby to handle articles with respect to the movable shelves ( 1 ) opposed to a working aisle (S) by using the working aisle (S) opened between the movable shelves ( 1 ). Each movable shelf ( 1 ) includes a pair of movement detectors ( 19 ) disposed in a left-right direction (B) perpendicular to the travel direction (A) of the movable shelves ( 1 ). Absolute coordinates of each movement detector ( 19 ) are found based on detection signals from the pair of movement detectors ( 19 ) of each movable shelve ( 1 ). The amount of left-right directional deviation from the travel path (i) of the movable shelves ( 1 ) is corrected based on the amount of deviation of the absolute coordinates in the left-right direction (B). Further, the attitude of the movable shelves ( 1 ) is corrected to be perpendicular to the travel direction (A) based on positional deviation of the absolute coordinates in the travel direction (A), i.e. traveled distance deviation.

TECHNICAL FIELD

The present invention relates to a shelving system with a plurality ofmovable shelves.

BACKGROUND ART

Conventionally, the following configuration is proposed for the abovetype of shelving system.

It is configured so that a constant travel path is arranged in a spacewithin a warehouse or a business office, a plurality of shelves (movableshelves) installed for back and forth movement is arranged on theconstant travel path leaving a space for a working aisle, a button forspecifying the necessary working aisle when the working aisle isnecessary between the movable shelves is provided on the movable shelfopposing, for example, the relevant working aisle, and one or aplurality of movable shelves self-advances along the constant travelpath until the space between the movable shelves specified in accordancewith the operation of the button reaches the width of the working aisle.Workers or cargo vehicles (e.g., fork lift) enter the working aisleopened between the movable shelves, and handling of articles isperformed to the movable shelves opposing such working aisle.

When the movable shelf is self-advanced, a width-deviation correctioncontrol is performed so that the movable shelf can move along the travelpath. For example, in JP-A 2000-142922, a position reference member(e.g., magnetic tape) is laid along the travel path, and by detectingsuch position reference member with a contact-subjecting positiondetector (e.g., magnetic sensor) for each movable shelf, the deviationfrom the travel path of the movable shelf is detected, and the movableshelf can move along the travel path while correcting the detecteddeviation.

Further, when the movable shelf is self-advanced, an attitude control isperformed to maintain the attitude of the movable shelf in a directionperpendicular to the travel path. For example, in JP-A 2001-48314, themoved distances of both ends in the right-and-left direction at rightangles to the travel direction of the movable shelf are each detected bycounting a pulse of a pulse encoder coupled to traveling wheels of themovable shelf, and attempt is made to eliminate the difference of themoved distances between such ends, that is, to maintain the attitude ofthe movable shelf in the direction at right angles to the travel path.

In the above-mentioned conventional configuration, when the movableshelf is self-advanced, in order to achieve a shelving system capable ofperforming both the width-deviation correction control and the attitudecontrol, the position reference member (magnetic tape) must be laid, andthe contact-subjecting position detector (magnetic sensor) for detectingthe position reference member must be provided on each movable shelf,and further, two pulse encoders must be arranged on each movable shelfto maintain the attitude of the movable shelf in the directionperpendicular to the travel path, thereby arising a problem of increasein cost.

In the movable shelf in which the position reference member is laid, andthe contact-subjecting position detector as well as the pulse encoderare provided, when the movable shelf is moved in a tilted manner, thetrajectory of the pulse encoder draws an arc, thereby causing an errorbetween the moved distances of both ends and the moved distance in thetravel direction, and arising a problem that an accurate attitudecontrol of the movable shelf can not be performed. Further, when themovable shelf is tilted, an error occurs in the moved distance in thedirection at right angles to the travel path detected by thecontact-subjecting detector.

It is therefore an object of the present invention to provide a shelvingsystem capable of accurately performing the width deviation correctioncontrol and the attitude control of a movable shelf and, further,reducing cost.

DISCLOSURE OF THE INVENTION

The present invention is directed to a shelving system comprising aplurality of movable shelves installed for back-and-forth movement on atravel path through a travel supporting device so as to handle articleswith respect to the movable shelves opposing a working aisle by usingthe working aisle opened between the movable shelves, wherein a pair ofmovement detecting means for detecting a moved distance in the traveldirection and a moved distance in a right-and-left direction for everyunit time is arranged in the right-and-left direction at right angles tothe travel direction along the travel path of each movable shelf, andcontrol means for controlling the movable shelves is also arranged.

The control means derives absolute coordinates of each movementdetecting means by the moved distance in the travel direction and themoved distance in the right-and-left direction each detected by eachmovement detecting means, corrects (performs width deviation correctioncontrol) the deviation in the right-and-left direction from the travelpath of the movable shelves involved in the traveling of the movableshelves based on the absolute coordinates, or corrects (performsattitude control) the attitude of the movable shelf in a direction atright angles to the travel direction based on the positional deviationin the travel direction of the absolute coordinates.

According to the above configuration, the width deviation correctioncontrol and the attitude control of the movable shelves are accuratelyperformed, and the detecting means for performing the width deviationcorrection control and the attitude control of the movable shelves mayonly be one pair of movement detecting means, thereby reducing the cost.

Further, the movement detecting means of the present invention includeslight projecting means and image pickup means, where the light isdiagonally irradiated from the light projecting means to the floor, andthe light reflected by the floor is received by the image pickup meansthereby picking up the image of the fine projections or depressions ofthe floor. Thus, the movement of the position of the picked up fineprojections or depressions of the floor is tracked by a distancedetecting means, and the moved distance in the travel direction and themoved distance in the right-and-left direction for every unit time arederived.

The movement detecting means of the present invention includes lightdetecting means and adjusting means in addition to the light projectingmeans and the image pickup means. The illuminance of the floor isdetected by the light detecting means, and when the illuminance of thefloor changes, such change is detected by the light detecting means, andthe detected illuminance of the floor is input to the adjusting means.The intensity of the light irradiated from the light projecting means isadjusted based on the detected illuminance of the floor by the adjustingmeans, and the intensity of the light received by the image pickup meansis maintained constant. Therefore, the illuminance (contrast) of thefine projections or depressions of the floor detected by the imagepickup means is maintained constant and the possibility ofdistinguishing or not distinguishing the fine projections or thedepressions of the floor by the contrast is avoided, and thus thedetection error is reduced.

Further, in the movement detecting means of the present invention, thelight projecting means and the image pickup means are arranged so thatthe light irradiated diagonally from the light projecting means to thefloor is reflected at approximately 90 degrees at the floor. Thus, thelight reflected at the floor is most efficiently received by the imagepickup means, and the difference between the light received by the imagepickup means and the light not traveling towards the image pickup meansdue to the fine projections and depressions of the floor becomes clear,thereby improving the precision for detecting the fine projections anddepressions of the floor.

In the movement detecting means, the light projecting means is arrangedso that the direction of the light irradiated by the light projectingmeans coincides with the travel direction of the movable shelves, andthe fine projections and depressions of the floor are continuouslydetected along the travel direction of the movable shelves. Thedetection of the moved distance in the travel direction thereby becomessmooth.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a shelving system according to anembodiment of the present invention;

FIG. 2 is a front view of the shelving system;

FIG. 3 is a partial plan view of a movable shelf of the shelving system;

FIG. 4 is a partially cutaway plan view of a main part of the movableshelf of the shelving system;

FIG. 5 is a side view of travel driving means and moving means of themovable shelf of the shelving system;

FIG. 6 is a circuit configuration diagram of the shelving system;

FIG. 7 is an explanatory view of a movement detector of the shelvingsystem;

FIG. 8 is a control block diagram of a controller of each movable shelfof the shelving system;

FIG. 9 is a control block diagram of a controller of each movable shelfof the shelving system; and

FIG. 10 is a control block diagram of a controller of each movable shelfof the shelving system.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will now be described in detail in conjunctionwith the accompanying drawings.

FIG. 1 is a perspective view of a shelving system according to anembodiment of the present invention; FIG. 2 is a front view of a movableshelf of the shelving system; FIG. 3 is a plan view of the movable shelfof the shelving system; FIG. 4 is a partially cut-out plan view of amain part of the movable shelf of the shelving system; and FIG. 5 is aside view of a travel supporting device and a movement detector of themovable shelf of the shelving system.

In FIGS. 1 to 5, a plurality (three in the figure) of a non-rail typemovable shelves 1 (hereinafter, referred to as movable shelf) travelingback and forth in a free manner on a floor 2 along a constant travelpath i by way of a travel supporting device (to be described later) isarranged on the floor 2. A fixed shelf 5 is arranged on both sides in adirection (hereinafter, referred to as a front-and-back direction) A ofthe travel path i of a first group of movable shelf 1 while providing anopened working aisle S.

The plurality of movable shelves 1 is referred to as a No. 1 movableshelf 1, a No. 2 movable shelf 1, and a No. 3 movable shelf 3 in theorder from the back towards the front in the front-and-back direction A.An aisle number of the working aisle S opened between the fixed shelf 5at the back and the No. 1 movable shelf 1 is “1”, the aisle number ofthe working aisle S opened between the No. 1 and No. 2 movable shelves 1is “2”, the aisle number of the working aisle S opened between the No. 2and No. 3 movable shelves 1 is “3”, and the aisle number of the workingaisle S opened between the No. 3 movable shelf 1 and the fixed shelf 5at the front is “4”.

A plurality of supporting columns 11, a plurality of front-and-backframes 12 coupled across each supporting columns 11 with a predeterminedspacing in the up-and-down direction, and a plurality of right-and-leftframes 13, coupled in the B direction (hereinafter, referred to asright-and-left direction) at right angles to the travel direction iacross each front-and-back frames 12, for supporting a palette P onwhich an article F is mounted are formed on each movable shelf 1 andeach fixed shelf 5. Further, a plurality of article accommodatingsections 14 is formed in the up-and-down direction and theright-and-left direction B with the plurality of supporting columns 11,the front-and-back frames 12, and the right-and-left frames 13. Theworker uses the working aisle S opened between the movable shelves 1 orbetween the movable shelf 1 and the fixed shelf 5 at the front or theback to carry out handling of the palette P on which the article F ismounted with a cargo vehicle G such as a fork lift with respect to anarticle accommodating section 14 of the movable shelf 1 or the fixedshelf 5 facing the working aisle S.

A traveling section (lower frame section) 15 traveling while supportingthe plurality of article accommodating sections 14 is arranged on eachmovable shelf 1. The traveling section 15 is configured by a lower framebody 18, a travel supporting device supported by the lower frame body18, and two movement detectors (one example of movement detecting means)19 including an optical mouse encoder arranged on both ends in theright-and-left direction B at the center in the front-and-back directionA of the movable shelf 1 and supported by the lower frame body 18.

As shown in FIGS. 3 to 5, the lower frame body 18 is formed into arectangular frame by a side lower frame 18 a positioned on both rightand left sides with respect to the front-and-back direction A of themovable shelf 1, an intermediate lower frame 18 b positioned at fivelocations (a plurality of locations) on the inner side of the movableshelf 1, four (a plurality of) coupling members 18 c in theright-and-left direction B coupled between the side lower frame 18 a andthe intermediate lower frame 18 b, a cross member 18 d in thefront-and-back direction arrange at a plurality of locations between thecoupling members 18 c, a plurality of braces 18 e, and the like. Theside lower frame 18 a and the intermediate lower frame 18 b are eachformed into a gate shape with an opened lower surface by a pair of sideplates and an upper plate arranged between the upper ends of both sideplates. The cross section of the coupling member 18 c and the crossmember 18 d is formed into a rectangular tube shape.

Four supporting columns 11 are erected on each the side lower frames 18a of both the right and left sides, and the intermediate lower frames 18b at five locations on the inner side (total of 28), and the pair ofsupporting columns 11 are coupled by a sub-beam 16 (FIG. 5) in thefront-and-back direction A.

The traveling wheels 20 are arranged as the travel supporting device atsix locations (a plurality of locations) in the right-and-left directionB and at two locations (a plurality of locations) in the front-and-backdirection A along the travel path i. The traveling wheels 20 areconfigured by an inner ring body 20 p made of metal, and an outer ringbody 20 r made of hard urethane rubber, and is configured so as tofreely roll on the floor 2 by way of the outer ring body 20 r. Further,the two (at least one) traveling wheels on both ends in theright-and-left direction B is cooperatively coupled to travel drivingmeans 23 arranged directly on the lower frame body 18 by passing thelinkage shaft 21 to the wheel shaft 20 q of the traveling wheel, therebyconfiguring a drive traveling wheel 20A. Each travel driving means 23 isformed by an induction motor 24, and a reduction gear 25 linked to themotor shaft thereof.

An approach detector (one example of approach detecting means) 31including a reflective photoelectric switch for detecting the approachof the movable shelf 1 or the fixed shelf 5 facing the movable shelf 1and inhibiting the approaching movement of each other is arranged on thesupporting column 11 on the left side lower frame 18 a and on a surface(hereinafter, referred to as the side surface) facing the working aisleS thereof. The approach detector 31 is arranged at two locations in thefront-and-back direction A in the No. 1 movable shelf 1, and at onelocation at the front in the No. 2 and No. 3 movable shelves 1.

An operation panel 33 is arranged on a surface (hereinafter, referred toas a front surface) formed by the plurality of supporting columns 11 onthe left side lower frame 18 a, and an operation button 35 for selectingand operating the working aisle S for each working aisle S is arrangedon the front surface of each operation panel 33. The operation buttons35 corresponding to the working aisles S1, S2, S3, S4 are referred to asan S1 operation button 35, an S2 operation button 35, an S3 operationbutton 35 and an S4 operation button 35. The S operation button 35 andthe S2 operation button 35 are arranged at both end positions in thefront-and-back direction A of the No. 1 movable shelf 1, the S3operation button 35 is arranged at the front end position of the No. 2movable shelf 1, and the S4 operation button 35 is arranged at the frontend position of the No. 3 movable shelf 1.

A controller (one example of controlling means) 36 (FIG. 6) including amicrocomputer, and an inverter 37 (FIG. 6) for driving the motor 24 ofeach travel driving means 23 are each arranged inside the operationpanel 33 of each movable shelf 1.

As shown in FIG. 6, the two movement detectors 19 on the right and theleft, the approach detectors 31, the operation buttons 35, and the twoinverters 37 of each movable shelf 1 are connected to the controller 36of each movable shelf 1, and further, the controllers 36 of each movableshelf 1 are connected to each other. The front and back approachdetectors 31 and the front and back S1, S2 operation buttons 35 areconnected to the controller 36 of the No. 1 movable shelf 1. Thereciprocal drive of the motor 24 is carried out by outputting a motordrive signal (speed command value including move-forward/move-backwardsignal) to the two inverters 37 from each controller 36, and operatingeach inverter 37 in response to the motor drive signal. The movableshelf 1 can then be traveled back and forth, and a difference in speedbetween the right and left motors 24 is created to eliminate the widthdeviation of the movable shelf 1 and to correct the attitude of themovable shelf 1 (to be described in detail later).

As shown in FIGS. 1 and 3, a horizontal cable arm 39 is retractablyarranged between the fixed shelf 5 and the movable shelf 1 and betweenthe movable shelves 1 to supply power to the inverter 37 and thecontroller 36 and to transmit or receive signals between controllers 36.

Further, as shown in FIGS. 1 and 2, a power box 41 for the shelvingsystem is arranged on the front surface of the back fixed shelf 5. Asshown in FIG. 6, an over current circuit-breaker (breaker) 42 for amovable shelf drive power source connected to the commercial powersource line (corresponding to the drive power source of each movableshelf 1), a control power source (not shown) for supplying control powerto the controller 36 of each movable shelf 1, and an over currentcircuit-breaker (breaker) 43 for a control power source connected to thecontrol power source device are arranged in the power box 41, where thedrive power source and the control power source are supplied to eachmovable shelf 1 via the breakers 42, 43 and the horizontal cable arm 39.

The configuration and the detecting principle of the movement detector19 will now be explained with reference to FIG. 7.

As mentioned above, the pair of movement detectors 19 are each arrangedon both ends in the right-and-left direction B at the center in thefront-and-back direction A of the movable shelf 1, and supported by thecoupling member 18 c at the center of the lower frame body 18. As shownin FIG. 7(a), each movement detector 19 is configured by a lightemitting diode (LED: one example of light projecting means) 51, a lens52, an image pickup device (CCD: one example of image pickup means) 53,a distance detector (one example of distance detecting means) 54, aphotosensor (one example of light detecting means) 55, an adjustingcircuit (one example of adjusting means) 56, and a control power circuit57.

The light emitting diode 51 diagonally irradiates a pulse light L atabout one million times a second so that the direction of lightirradiated to the floor 2 where the movable shelf 1 is arrangedcoincides with the travel direction A of the movable shelf 1.

The lens 52 collects the pulse light L irradiated from thelight-emitting diode 51 and reflected by the floor 2.

The image pickup device 53 receives the pulse light L collected by thelens 52, and picks up the image of the fine projections 2 a anddepressions 2 b of the floor 2.

The arranging positions of the light emitting diode 51, the lens 52 andthe image pickup device 53 are adjusted so that the angle δ created bythe light irradiated by the light emitting diode 51 and the pulse lightL received by the image pickup device 53 by way of the lens 52 isapproximately 90 degrees.

The photosensor 55 detects the illuminance of the floor 2 on where themovable shelf 1 is arranged (illuminance of the floor 2 at where themovement detector 19 is arranged).

The adjusting circuit 56, based on the illuminance of the floor 2detected by the photosensor 55, controls the current value to beprovided to the light emitting diode 51 and adjusts the intensity of thelight irradiated by the light emitting diode 51 so that the intensity ofthe pulse light L received by the image pickup device 53 is constant.

The control power circuit 57, connected to the control power source(FIG. 6), adjusts the voltage to a predetermined voltage and supplies itto the distance detector 54 and the adjusting circuit 56.

As shown in FIG. 7(b), the distance detector 54 digitalizes the imagepickup signal of the image pickup device 53 to a signal level (thresholdvalue) set in advance, and forms a contrast pattern (pattern in whichthe fine projections 2 a or depression 2 b is the dark part). It furtherstores the position of the pixel D of the image pickup device 53detecting the projection 2 a or depression 2 b in accordance with andfor each irradiation of the pulse light L, tracks the position of thepixel D moving in the direction opposite the moving direction along thetravel direction A, derives the distance x, y (the distance between thepixels D is set in advance) which the distance detector 54 has moved foreach predetermined time t, and outputs the same to the controller 36with the synchronization signal s. Here, the spacing of the pixel D isequal to or less than about 50 μm, and a problem in the output precisiondoes not occur even if the image pickup device 53 is tilted on the planesurface since the pixel D of the CCD detecting the projection 2 a anddepression 2 b is tracked in accordance with the irradiation of thepulse light.

In this way, the light is irradiated diagonally with respect to thefloor 2 along the travel direction A of the movable shelf 1 from thelight-emitting diode 51, and the light reflected by the floor 2 isreceived by the image pickup device 53. The fine projections 2 a ordepressions 2 b of the floor 2 in a long range in the travel direction Aare thereby imaged, the movement of the position (pixel D) of the fineprojections 2 a or depressions 2 b of the floor 2 picked up by the imagepickup device 53 is tracked by the distance detector 54, and the moveddistance x in the travel direction A and the moved distance y in theright-and-left direction B for every unit time t are obtained.

The adjusting circuit 56, based on the illuminance of the floor 2detected by the photosensor 55, adjusts the intensity of the lightirradiated by the light emitting diode 51, and thus the illuminance(contrast) of the fine projections 2 a or depressions 2 b of the floor 2are held constant even if the illuminance of the floor 2 is changed, andthe intensity of the light received by the image pickup device 53 isheld constant.

The operation of the controller 36 of the movable shelf 1 will now beexplained in accordance with the control block diagrams of FIGS. 8 to10.

As shown in FIGS. 8 and 9, the controller 36 is configured by asimultaneous operation detecting unit 60, a speed control section 61,first counters 62L, 62R, front/back distance calculating units 63L, 63Ron the right and the left, second counters 64L, 64R, left/right distancecalculating units 65L, 65R on the right and the left, a calculating unit66, a mean calculating unit 67, and a plurality of logic circuits.

The first counter 62L on the left counts the distance x for every unittime input from the left movement detector 19 each time thesynchronization signal s of the left movement detector 19 is input tothe controller 36.

The first counter 62R on the right counts the distance x for every unittime input from the right movement detector 19 each time thesynchronization signal s of the right movement detector 19 is input tothe controller 36.

The front/back distance calculating unit 63L on the left calculates thefront/back moved distance X_(L) of the position of the movement detector19 from the counted value of the first counter 62L.

The front/back distance calculating unit 63R on the right calculates thefront/back moved distance X_(R) of the position of the movement detector19 from the counted value of the first counter 62R.

The second counter 64L on the left counts the distance y for every unittime input from the left movement detector 19 each time thesynchronization signal s of the left movement detector 19 is input.

The second counter 64R on the right counts the distance y for every unittime input from the right movement detector 19 each time thesynchronization signal s of the right movement detector 19 is input.

The left/right distance calculating unit 65L on the left calculates theleft/right moved distance Y_(L) of the position of the movement detector19 from the counted value of the second counter 64L.

The left/right distance calculating unit 65R on the right calculates theleft/right moved distance Y_(R) of the position of the movement detector19 from the counted value of the second counter 64L.

The subtracter 66 subtracts the moved distance X_(R) of the rightmovement detector 19 calculated from the front/back distance calculatingunit 63R on the right from the moved distance X_(L) of the left movementdetector 19 calculated from the front/back distance calculating unit 63Lon the left to derive the traveled distance deviation (movement to theleft is positive).

The mean value calculating unit 67 calculates the mean value of themoved distance Y_(L) of the left movement detector 19 calculated fromthe left/right distance calculating unit 65L on the left and the moveddistance Y_(R) of the right movement detector 19 calculated from theleft/right distance calculating unit 65R on the right to derive theamount of deviation (deviation in the left direction is positive) to theright and the left from the travel path i.

Therefore, the absolute coordinates (X_(L), Y_(L)) of the left movementdetector 19, the absolute coordinates (X_(R), Y_(R)) of the rightmovement detector 19, the traveled distance deviation, and the amount ofdeviation are derived from the detection signals (distance x, y andsynchronization signal s) of the right and left movement detectors 19.

The worker operates the S2, S3, S4 operation buttons 35, excluding theS1 operation button 35, and the movable shelves 1 of which operationbutton 35 is operated, and all the movable shelves 1 on the back side ofsuch movable shelves 1 must move backwards, and all the movable shelves1 on the front side of the movable shelf 1 of which operation button 35is operated must move forward to form the working aisle S at the frontof the movable shelf 1 of which operation button 35 is operated. Whenthe S1 operation button 35 is operated, all the movable shelves 1 mustmove forward to form the working aisle S at the back of the No. 1movable shelf 1. Further, when at least two operation buttons 35 aresimultaneously operated, it is determined to be a wrong operation, andthe movement of the movable shelf 1 must be locked (stopped).

When the operation command of the S2, S3, S4 operation buttons 35,excluding the S1 operation button 35, is input to the controller 36 ofeach movement shelf 1, an in-operation signal of the operation button 35is output to the controller 36 of the other movement shelves 1, and amove-backward command is output to the controllers 36 of all themovement shelves 1 on the back side, and the move-forward command isoutput to the controllers 36 of all the movement shelves 1 on the frontside while the operation command is being input. Further, when theoperation command of the S1 operation button 35 is input to thecontroller 36 of the No. 1 movement shelf 1, the in-operation signal ofthe operation button 35 is output to the controller 36 of the movementshelves 1 on the front side, and the move-forward command is outputwhile the operation command is being input.

The simultaneous operation detecting unit 60 holds the in-operationsignal (operation signal command) of the operation button 35 of themovable shelf 1 provided with the controller 36 and the in-operationsignal from the other controllers 36 for a predetermined time, and formsa combination of the in-operation signal of the two operation buttons35. The logical product (AND) of the operation signals of the twooperation buttons 35 held over a predetermined time is obtained for eachcombination, and the logical sum (OR) of the output of such logicalproduct are taken and then output. Thus, at least two of the operationbuttons 35 are detected (determined) whether operated substantiallysimultaneously, and then output.

The speed control section 61 is input with the move-backward command,which will be described later, the traveled distance deviation, theamount of deviation, and the move-forward command and makes an outputwith a speed difference between the speed of the two motors 24 so as tocorrect the attitude of the movement shelf 1 and to eliminate the amountof deviation with the traveled distance deviation.

When the operation command of the operation button 35, or themove-backward command from the controller 36 of the front movable shelf1 is input to the OR circuit, a check is made by the AND circuit whetherthe move-backward stop command (to be described later) from thecontroller 36 of the movable shelves 1 adjacent at the back is input, orwhether the output of the simultaneous operation detecting unit 60 isturned ON (ON when at least two operation buttons 35 are determined tobe simultaneously operating). Further, when the move-backward stopcommand from the controller 36 of the adjacent movable shelves 1 is notinput, and the output of the simultaneous operation detecting unit 60 isnot turned ON, the AND circuit outputs the move-backward command to thespeed control section 61.

The speed control section 61, when input with the move-backward command,sets the speed difference of the two motors 24 in accordance with thetraveled distance deviation and the amount of deviation, and outputs themotor drive signal (speed command value) to move backwards to the twoinverters 37. The movable shelf 1 moves backwards while eliminating thetraveled distance deviation and the amount of deviation since each motor24 is driven backwards by the two inverters 37.

Further, when the move-backward stop command from the controller 36 ofthe movable shelves 1 adjacent at the back is input to the AND circuit,the move-backward command to the speed control section 61 is turned OFF,and the movable shelf 1 comes to a stop. Even if the operation commandof the operation button 35 is input or the move-backward command fromthe controller 36 of the front movable shelf 1 is input, when themove-backward stop command is being input or when the output of thesimultaneous operation detecting unit 60 is turned ON, the move-backwardcommand is not output to the speed control section 61, and the movableshelf 1 remains stopped. When the operation command of the operationbutton 35 is being input, or when the move-backward command from thecontroller 36 of the front movable shelf 1 is being input, themove-backward command to the speed control section 61 is produced, andwhen the operation command of the operation button 35 and themove-backward command from the controller 36 of the front movable shelf1 are turned OFF, the move-backward command to the speed control section61 is turned OFF and the movable shelf 1 comes to a stop.

Further, when the move-forward command is input from the controller 36of the movable shelf 1 at the back to the OR circuit, a check is made bythe AND circuit whether the approach detector 31 is operating or not,and whether the output of the simultaneous operation detecting unit 60is turned ON or not. If the approach detector 31 is not operating andthe output of the simultaneous operation detecting unit 60 is not turnedON, the AND circuit outputs the move-forward command to the speedcontrol section 61.

When the move-forward command is input to the speed control section 61,the speed control section 61 corrects the attitude of the movable shelf1, sets the speed difference of the two motors 24 so as to eliminate theamount of deviation, and outputs the motor drive signal (speed commandvalue) to move forward to the two inverters 37. Each motor 24 is drivenforward by the two inverters 37 and thus the movable shelf 1 movesforward while eliminating the traveled distance deviation and the amountof deviation.

When the approach detector 31 is operating, the move-forward command tothe speed control section 61 is turned OFF, and the movable shelf 1comes to a stop. If the approach detector 31 is operating when themove-forward command is input from the controller 36 of the movableshelf 1 at the back, or when the output of the simultaneous operationdetecting unit 60 is turned ON, the move-forward command is not outputto the speed control section 61, and the movable shelf 1 remainsstopped. When the move-forward command is being input from thecontroller 36 of the movable shelf 1 at the back, the move-forwardcommand to the speed control section 61 is produced, and when themove-forward command from the controller 36 of the movable shelf 1 atthe back is turned OFF, the move-forward command to the speed controlsection 61 is turned OFF and the movable shelf 1 comes to a stop.Further, when the approach detector 31 is operating, the abovemove-backward stop command is output to the controllers 36 of themovable shelves 1 adjacent at the front.

As mentioned above, when the output of the simultaneous operationdetecting unit 60 is turned ON, that is, when two or more operationbuttons 35 are almost simultaneously operating (when wrongly operated),both the move-backward command and the move-forward command are notoutput and the movable shelf 1 remains stopped.

In the controller 36 of the No. 1 movable shelf 1, when the operationsignal of the S1 operation button 35 is input, the move-forward commandand the in-operation signal are output to the controllers 36 of all themovable shelves 1 on the front side, as mentioned above, and when theapproach detector 31 at the front is not operating, the move-forwardcommand is output to the speed control section 61. Further, in thecontroller 36 of the No. 1 movable shelf 1, when the approach detector31 at the back is operating, the move-backward command is turned OFF andthe backward movement of the movable shelf 1 comes to a stop. Theoperation signal of the S1 operation button 35 is input to thesimultaneous operation detecting unit 60.

FIG. 10 shows a detailed block diagram of the speed control section 61.

As shown in FIG. 10, the speed control section 61 is configured by arelay RY-F, a relay RY-B, a relay RY-S, a speed adjuster 71, a firstfunction unit 72, a second function unit 73, a first comparator 74, arelay RY-P, a third function unit 76, a fourth function unit 77, asecond subtracter 78, a first low limit limiter 79, a third subtracter80, a second low limit limiter 81, a second comparator 82, an off-delaytimer 83, and a plurality of logic circuits.

The relay RY-F operates when the move-forward command is input.

The relay RY-B operates when the move-backward command is input.

The relay RY-S operates when both the move-forward command andmove-backward command are not input, that is, during the stop command.

The speed adjuster 71 is set with a predetermined traveling speed of themovable shelf 1.

The first function unit 72 is configured so that the traveled distancedeviation input from the subtracter 66 is selected (input) when theoff-delay timer 83, which will be described later, is turned OFF, and sothat the no-distance deviation (deviation=0) is selected (input) whenthe timer 83 is turned ON, and derives the speed correction amount ofthe left drive traveling wheel 20A from the selected (input) deviation.Further, when the deviation exceeds a positive predetermined amount(dead band) and becomes positive, the positive speed correction amountis output in proportion therewith.

The second function unit 73, similar to the first function unit 72, isselected (input) with the traveled distance deviation or the no-distancedeviation (deviation=0) by the operation of the off-delay timer 83, andderives the speed correction amount of the right drive traveling wheel20A. Further, when the deviation exceeds a negative predetermined amount(dead band) and becomes negative, the positive speed correction amountis output in proportion therewith.

The first comparator 74 is, similar to the first function unit 72,selected (input) with the traveled distance deviation or the no-distancedeviation (deviation=0) by the operation of the off-delay timer 83, andoperates when the selected deviation exceeds a positive or negativepredetermined amount (dead band), that is, when the speed correctionamount is output from the first function unit 72 or the second function73, and the movable shelf attitude correction control (tilt correctioncontrol) is performed.

The relay RY-P is operated by the operation of the first comparator 74.

The third function unit 76 is configured so that the amount of deviationoutput from the mean value calculating part 67 is selected (input) whenthe relay RY-P is not operating, and the no-width deviation (amount ofdeviation=0) is selected (input) when the relay RY-P is operating, andderives the speed correction amount of the left drive traveling wheel20A from the selected amount of deviation. Further, when the amount ofdeviation exceeds a positive (width deviation to the left) predeterminedamount (dead band) and becomes positive, the positive speed correctionamount is output in proportion therewith.

The fourth function unit 77 is, similar to the third function unit 76,selected (input) with the amount of deviation or no-displacement (amountof deviation=0) by the operation of the relay RY-P to derive the rightspeed correction amount of the right drive traveling wheel 20A. Further,when the deviation exceeds a negative predetermined amount (dead band)and becomes negative, a positive speed correction amount is output inproportion therewith.

The second subtracter 78 subtracts the positive speed correction amountoutput from the first function unit 72 and the third function unit 73from the predetermined traveling speed of the movable shelf 1 set in thespeed adjuster 71, and derives the speed command value of the left drivetraveling wheel 20A.

The first low limit limiter 79 limits the lower limit of the speedcommand value of the left drive traveling wheel 20A obtained from thesecond subtracter 89 and guarantees the minimum speed, the outputthereof being selected to be the speed command value of the left drivetraveling wheel 20A in which the lower limit is limited by the operation(turned ON by the move-forward command) of the relay RY-F. Thereafter,it is configured so that a value in which the speed command value of theleft drive traveling wheel 20A in which the lower limit is limited bythe operation (turned ON by the move-backward command) of the relay RY-Bis negative is selected, the speed command value “0” of the left drivetraveling wheel 20A is selected by the operation (turned ON by the stopcommand) of the relay RY-S, and the speed command value is output to theleft inverter 37.

The third subtracter 80 subtracts the speed correction amount outputfrom the second function unit 73 and the fourth function unit 77 fromthe predetermined traveling speed of the movable shelf 1 set in thespeed adjuster 71, and derives the speed command value of the rightdrive traveling wheel 20A.

The second low limit limiter 81 limits the lower limit of the speedcommand value of the right drive traveling wheel 20A obtained from thethird subtracter 80 and guarantees the minimum speed, which output beingselected as the speed command value of the right drive traveling wheel20A in which the lower limit is limited by the operation (turned ON bythe move-forward command) of the relay RY-F. Thereafter, it isconfigured so that a value in which the speed command value of the rightdrive traveling wheel 20A in which the lower limit is limited by theoperation (turned ON by the move-backward command) of the relay RY-B isnegative is selected, the speed command value “0” of the right drivetraveling wheel 20A is selected by the operation (turned ON by the stopcommand) of the relay RY-S, and the speed command value is output to theright inverter 37.

The second comparator 82 is operated when the amount of deviation inputfrom the mean value calculating block 67 to the speed control section 61exceeds the positive or negative predetermined amount (dead band of thefunction units 76, 77).

The off-delay timer 83 is operated by the operation of the secondcomparator 82.

Here, the speed command value indicates a speed command value for theforward movement when positive, and the speed command value for thebackward movement when negative.

Due to the configuration of the speed control section 61, normally, whenthe move-forward command or the move-backward command is input to thespeed control section 61, based on the traveled distance deviation ofboth left and right ends arranged with the movement detector 19, themovable shelf attitude control is performed that outputs the speedcommand value with the speed difference between the two motors 24 toeliminate the traveled distance deviation, that is, to have the attitudeof the movable shelf 1 at right angles to the travel path i. When theamount of deviation in the right-and-left direction reaches apredetermined amount and the second comparator 82 is operated, themovable shelf width deviation correction control is performed thatoutputs the speed command value with a speed difference between the twomotors 24 to eliminate the amount of deviation in preference to themovable shelf attitude control. When the amount of deviation in theright-and-left direction falls within the predetermined amount due tosuch movable shelf width deviation correction control, the movable shelfattitude control is again performed after a time set by the timer 83.

The function by the configuration of the shelving system will now beexplained. As shown in FIG. 2, the working aisle S3 is formed betweenthe No. 2 and No. 3 movable shelves 1. Here, each of the approachdetectors 31 at the front and the back of the No. 1 movable shelf 1 andthe approach detector 31 of the No. 3 movable shelf 1 are operated(turned ON).

The worker can thereby open the working aisle S02 and carry out thetask.

The worker first checks that there is no one in the working aisle S3,and operates the S2 operation button 35 of the No. 1 movable shelf 1.The controller 36 of the No. 1 movable shelf 1 then, in response to theS2 operation button 35, outputs the move-backwards command to thecontroller 36 of the No. 1 movable shelf 1 of itself (at the back), andoutputs the move-forward command to the controllers 36 of the No. 2 andNo. 3 movable shelves 1 at the front. Since the back approach detector31 of the No. 1 movable shelf 1 is turned ON, the No. 1 movable shelf 1remains stopped without moving backwards, and further, since theapproach detector 31 of the No. 3 movable shelf 1 is turned ON, the No.3 movable shelf 1 remains stopped without moving forward.

The No. 2 movable shelf 1 starts to move forward. While the workeroperates the S2 operation button 35, a command is output to thecontroller 36 of each movable shelf 1, and when the worker stops theoperation of the S2 operation button 35, the command is turned OFF andthe No. 2 movable shelf 1 comes to a stop.

Since the traveled distance deviation and the amount of deviation areinput to the speed control section 61 while the No. 2 movable shelf 1 ismoving forward, the speed of the two motors 24 is controlled so as tocorrect the attitude of the movable shelf 1 from the above-mentionedtraveled distance deviation and to eliminate the amount of deviation.

When the No. 2 movable shelf 1 moves forward and the forward approachdetector 31 of the No. 2 movable shelf 1 is turned ON, the move-forwardcommand is turned OFF, and the No. 2 movable shelf 1 approaches the No.3 movable shelf 1 and stops, thereby opening the working aisle S2.Further, the move-backward command is output from the controller 36 ofthe No. 2 movable shelf 1 to the controller 36 of the No. 3 movableshelf 1.

The worker, when the working aisle S2 is formed, enters the workingaisle S2 and performs the article handling task.

When the worker stops the operation of the operation button 35 and theoperation command thereof is turned OFF, the move-forward command andthe move-backward command to the speed control section 61 (inverter 37)are turned OFF, and the movable shelf 1 comes to a stop. In this way, bystopping the operation of the operation button 35 while the movableshelf 1 is moving and stopping the movement of the movable shelf 1, theS2 or S3 aisle to which the worker can enter is formed as he or shepleases. Even if the movable shelf 1 is stopped while the working aisleS is being formed, and for example, when the S2 aisle and the S3 aisleare formed, the moving direction of the movable shelf 1 moved inaccordance with the opened working aisle S is determined in response tothe operation of the operation button 35, and the speed control section61 (inverter 37) is controlled by the determined moving direction, thusallowing the target working aisle S to be formed.

According to the above-mentioned embodiment, the absolute coordinates,that is, the above-mentioned (X_(L), Y_(L)) and (X_(R), Y_(R)) of theposition of each movement detector 19 (right and left direction) of eachmovable shelf 1 are obtained by the moved distance x in thefront-and-back direction A and the moved distance y in theright-and-left direction B for every unit time each detected by eachmovement detector 19 (right-and-left direction) of each movable shelf 1.The deviation in the left-right direction B from the travel path i ofthe movable shelf 1 is corrected based on the amount of deviation in theright-and-left direction of such absolute coordinates involved in thetraveling of the movable shelf 1, thereby allowing the width deviationcorrection control of the movable shelf 1 to be accurately performed.Further, as the positional deviation (i.e., tilt of the attitude of themovable shelf 1) in the travel direction of each movement detector 19 iscorrected so as to be at right angles to the front-and-back direction Abased on the positional deviation (i.e., traveled distance deviation) inthe travel direction of the absolute coordinates, the attitude controlof the movable shelf 1 can be accurately performed. Further, thedetection-subjected body (e.g., magnetic tape 91) laid along the travelpath i and the detector (e.g., magnetic sensor 93) for detecting thedetection-subjected body, as in the conventional art, becomeunnecessary, and thus the cost can be reduced.

According to the present embodiment, the intensity of the light receivedby the image pickup device 53 is adjusted by the adjusting circuit 56 soas to be constant and the current value supplied to the light emittingdiode 51 is controlled based on the illuminance of the floor 2 detectedby the photosensor 55. In such way, as the intensity of the lightirradiated by the light emitting diode 51 is adjusted, the contrast ofthe fine projections 2 a and depressions 2 b of the floor 2 can bemaintained constant even if the illuminance of the floor 2 is changed.Therefore, even if the threshold value for digitalizing the image pickupsignal of the image pickup device 53 is a fixed value, the possibilityof distinguishing or not distinguishing the fine projections 2 a ordepressions 2 b of the floor 2 by the contrast (illuminance) can beavoided, thereby forming a stable contrast pattern and allowing a stabletracking of the projection 2 a and the depression 2 b. The detectionerror can be also reduced.

According to the present embodiment, the light L diagonally irradiatedto the floor 2 by the light emitting diode 51 is reflected at the floor2 at approximately 90 degrees, and received by the image pickup device53. Thus, the light L reflected by the floor 2 is most efficientlyreceived by the image pickup device 53, and the difference between thelight received by the image pickup means and the light not travelingtowards the image pickup device 53 due to the fine projections 2 a ordepressions 2 b of the floor 2 become clear. Therefore, the precisionfor detecting the fine projections 2 a or depressions 2 b of the floor 2can be improved.

According to the present embodiment, the direction of the light Lirradiated by the light emitting diode 51 coincides with the traveldirection (front-and-back direction A) of the movable shelf 1, and thusthe fine projections 2 a or depressions 2 b of the floor 2 arecontinuously detected in a long range in the travel direction(front-and-back direction A) of the movable shelf 1, thereby allowingsmooth detection of the moved distance x in the travel direction.

In the present embodiment, the width deviation correction control andthe attitude control of the movable shelf 1 are performed, but thetraveling deviation from the target traveling position of the movableshelf 1 may be corrected, that is, positional control of the movableshelf 1 may be performed. Here, when the absolute moved distance of themovable shelf 1 is obtained from the mean value of the absolutecoordinates X_(L), X_(R) in the front-and-back direction A of eachmovement detector 19, and the target traveling distance to the targettraveling position is set, the deviation between the set value and theabsolute moved distance of the movable shelf 1 is obtained, and thespeed command value is output to the inverter 37 so that such deviationbecomes “0”.

In the present embodiment, the movement detector 19 serving as themovement detecting means is arranged on both ends in the right-and-leftdirection B of the movable shelf 1, but is not limited to both ends andonly needs to be in the right-and-left direction B, and is not limitedto two, and more than two movement detectors 19 may be arranged on themovable shelf 1 to obtain the absolute coordinates of theses movementdetectors 19 to perform the width deviation correction control and theattitude control, or the positional control of the movable shelf 1.

In the above-mentioned embodiment, the shelving system is configured sothat a plurality of movable shelves 1 is arranged between the fixedshelves 5 at the front and the back, but considering the configurationin which a plurality of movable shelves 1 is arranged between the frontand back fixed shelves 5 as one block, the shelving system may beconfigured by a plurality of such blocks. The configuration may also besuch that a plurality of movable shelves 1 is arranged between the wallswith a space for the working aisle S (configuration without the fixedshelves 5 on both sides or configuration without one of the fixed shelf5).

In the present embodiment, the power box 41 is arranged in the fixedshelf 5, but is not limited to the fixed shelf 5, and the power box 41may be arranged on the movable shelf 1 or the wall surface of awarehouse and the like in which such shelving system is installed.

In the present embodiment, the photoelectric switch serving as theapproach detector 31 is used, but is not limited to the photoelectricswitch, and may be any as long the approach of the movable shelf 1 orthe fixed shelf 5 is detected. The magnetic sensor, for example, may beused. When the magnetic sensor is used, an object for generating amagnetic force such as a magnet is attached to the surface of themovable shelf 1 or the fixed shelf 5 facing the magnetic sensor.

In the present embodiment, the article accommodating section 14 of atype for carrying out placement and accommodation of the article F byway of the palette P is proposed on the assumption that it is installedin the warehouse for handling the article F with the cargo vehicle Gsuch as a fork lift, but may be a type in which the article F or a caseis directly placed and accommodated on the assumption that it isinstalled in the business office.

In the present embodiment, the article accommodating section 14 isformed in the up-and-down direction and in the right-and-left directionby the supporting columns 11, the front-and-back frames 12 and theright-and-left frames 13, but the article accommodating section 14 maybe a type other than the above type. For example, it may be a type inwhich the article accommodating section 14 is formed in the up-and-downdirection and in the left-right direction by the supporting column 11and the shelf plate 12, or a type in which only one step of articleaccommodating section 14 is formed.

In the present embodiment, the traveling wheel 20 serving as thetraveling supporting device is shown, but may also be a caterpillar type(roller chain type).

In the present embodiment, the intensity of the light received by theimage pickup device 53 is adjusted by the adjusting circuit 56 so as tobe constant, the current value supplied to the light-emitting diode 51is controlled, and the intensity of the light irradiated by thelight-emitting diode 51 is adjusted based on the illuminance of thefloor 2 detected by the photosensor 55, but the signal level (thresholdvalue) for digitalizing the image pickup signal of the image pickupdevice 53 of the distance detector 54 may be adjusted based on theilluminance of the floor 2 detected by the photosensor 55. With suchconfiguration as well, the possibility of distinguishing or notdistinguishing the fine projection 2 a or depression 2 b of the floor 2by contrast (illuminance) can be avoided, thereby forming a stablecontrast pattern, and allowing a stable tracking of the projections 2 aor depressions 2 b. Further, the detection error is reduced.

1. A shelving system comprising a plurality of movable shelves installedfor back-and-forth movement on a travel path through a travel supportingdevice thereby to handle articles with respect to the movable shelvesopposed to a working aisle by using the working aisle opened between themovable shelves, wherein the system further comprises: at least twomovement detecting means for detecting a moved distance in the traveldirection and a moved distance in a right-and-left direction for everyunit time, said means being provided in the right-and-left direction atright angles to the travel direction along the travel path of eachmovable shelf; and control means for finding absolute coordinates ofeach movement detecting means from the moved distance in the traveldirection and the moved distance in the right-and-left direction eachdetected by each movement detecting means, correcting a deviation in theright-and-left direction from the travel path of the movable shelvesinvolved in the traveling of the movable shelf or the deviation in thetravel direction of the movable shelf based on the absolute coordinates,and correcting an attitude of the movable shelf in a direction at rightangles to the travel direction or in the travel direction is alsoarranged.
 2. The shelving system according to claim 1, wherein themovement detecting means comprises: light projecting means fordiagonally irradiating light to a floor having the movable shelfarranged thereon; image pickup means for receiving the light irradiatedby the light projecting means and reflected by the floor, and picking upan image of a fine projection or depression of the floor; and a distancedetecting means for detecting the moved distance in the travel directionand the moved distance in the right-and-left direction for every unittime by tracking the movement of the position of the fine projection ordepressions of the floor picked up by the image pickup means.
 3. Theshelving system according to claim 2, wherein the movement detectingmeans comprises: light detecting means for detecting an illuminance ofthe floor having the movable shelf arranged thereon; and adjusting meansfor adjusting an intensity of the light irradiated by the lightprojecting means so that the intensity of the light received by theimage pickup means becomes constant based on the illuminance of thefloor detected by the light detecting means.
 4. The shelving systemaccording to claim 2, wherein the light projecting means and the imagepickup means are arranged so that an angle formed by the lightirradiated by the light projecting means and the light received by theimage pickup means is approximately 90 degrees.
 5. The shelving systemaccording to claim 2, wherein the light projecting means is arranged sothat the direction of the light irradiated by the light projecting meanscoincides with the travel direction of the movable shelves.